ECN 1024021

Sometimes it is necessary to operate two or more pumps in conjunction with one another. The operationwill be either parallel or series depending on the arrangement. Refer to FIGURE 2-4.

In a parallel operation, the discharge head is equal to that of one pump, and the volume is equal to the totalof the two. In this case, care should be exercised with the suction manifold to insure that one pump doesnot starve. Also the discharge capabilities of each pump should be fairly close to avoid one pump movingfluid back through the second pump.

The results of a series operation is the opposite of parallel systems. The volume is limited to the capacityof one pump but the head is equal to the sum of the two. This occurs because performance curves denotethe differential head across the pump so the second pump will add its head to the head supplied to its suctinby the first pump. If this is attewmpte4d, it is imperative to know the maximum working case pressure ofthe pump to avoid bursting the second pump. In oil field service, this type of hook up is seldom if everused, never with slurry, In industrial service, it is done on a limited basis pumping fluids. Due to the highincidence of seal failure in the second pump, this type if operation should be discouraged.

EXAMPLE

Two pumps, each having the capacity of 20 BPM @ 100 ft. of head, are to be operated together. Theoutput for parallel and series operations is as follows:

Parallel Operations:Volume = 20 BPM + 20 BPM = 40 BPMHead = 100 ft.

Series Operation:Volume = 20 BPMHead = 100 + 100 = 200 ft.

Although the theoretical head for series operation is 200 ft., the actual head will be somewhat lower. Thisis due to the friction loss in the manifold between pumps and will vary with volumes and manifold.

Gardner Denver Product Pumps4747 South 83rd East AvenueTulsa, Oklahoma 74145

(800) 637-8099 (918) 664-1151 Fax (918) 664-6225

Email: sales@gardnerdenvertulsa.comWebsite: www.gardnerdenver.com